This invention relates to diaphragm pumps, and in particular, to those pumps mountable within a sewing machine for use with a pneumatic needle threading assist.
Needle threading is a desirable feature to have on a sewing machine. Of the various types of needle threaders available, pneumatic needle threaders, as described in U.S. Pat. No. 3,486,472 of R. M. Kaplan, use an air vacuum to pull the thread end through the eye of a sewing needle. While a manual pump may be used to supply the air vacuum, diaphragm pumps are available for this purpose having an actuating mechanism external to the pump itself. Bearing in mind the limited amount of space within the frame of a sewing machine, it becomes necessary to mount the pump and its actuating mechanism outside of the sewing machine frame, which in the case of industrial machines is acceptable. However, with respect to household sewing machines, it is desirable to mount the entire pump mechanism within the frame of the sewing machine.